On Sun, 30 Aug 2020 18:29:08 +0100, Dave W
wrote:

snip

Have you tried using an Allen key? As they are 6-sided perhaps one
would jam into the six gaps between the pins?

I think it's one of those optical illusion things Dave, where you can
see the head of the screw as a hole or a dome.

https://photos.app.goo.gl/UVzMuB43adyfNWJ58

https://en.wikipedia.org/wiki/File:B...ollow_Face.jpg

If you look at is as I believe it is, a dome, then the tool to turn it
wouldn't go in but 'over' the dome with inward facing 'splines' to
engage with the 'slots' in the screw head, like this:

https://www.i-sells.co.uk/images/100...IVER-BIT-1.jpg

A diy solution would be to find a fairly fine flat-bladed driver that
will fit in the recesses the screws are normally set in and grind a
slot out of the middle, the depth of the slot the height of the dome
and the width the distance between two opposing grooves. Then hope
it's strong enough to undo all the screws [1] without breaking. ;-)

Cheers, T i m

[1] There is normally at least *one* that won't budge. ;-)